What is spyware in respect of computer software?

• A. Software that aims to gather information about a person without his/her knowledge, and that may send such information to another entity.
• B. Legitimate software that allows companies to monitor and supervise the computers of their employees from a central location.
• C. Software used to disrupt computer operation or gain access to private computer systems.
• D. A computer program hidden within another seemingly harmless program that produces copies of itself into another programs or files.